Abstract
A batch method was developed for the determination of uranium (VI) in sea water by usingamidoxime resin as an adsorbent. The analytical procedure by standard addition is as follows.Put 5 liters of filtered sea water, 1 cm3 of 5, 7. 5, or 10 ppm uranium (VI), and 2g of the resin (Daia Ion CR-50) into three 5-liter beakers, respectively. Stir for four days. Filter the resin toseparate it from sea water, transfer the resin into a 50cm3 beaker, add 20cm3 of sulfuric acid, and shake it 3h. After filtering off the resin, transfer 10cm3 of the filtrate, 3cm3 of nitric acid, 2cm3 of 5% ascorbic acid, and 2 cm3 of 2% sodium fluoride into a 100-cm3 separatory funnel andextract uranium (VI) with 5 cm3 of TOPO in cyclohexane. After removing the aqueous phaseand washing the organic phase twice with 10-cm3 of the 2 mol dm-3 nitric acid, transfer the organicphase into a 10cm3 volumetric flask and add 1cm3 of the 0.05% 5-Br-PADAP, 0.5 cm3 of 10%TEA, and made up to the mark with ethanol. Allow this to stand for 30 min and measure theabsorbance of the colored solution at 575 nm against the reagent blank. The analytical result was2.8 μg of U (VI) /liter of sea water. Taking into accout the analytical results of other ions suchas sulfate (2.67×10-2mol dm-3), chloride (4.82×10-1 mol dm-3), magnesium (II)(4.33×10-2 mol dm-3), and calcium (II)(8.67×10-3 mol dm-3), it seems that the result is satisfactory.
